1. Field of the Invention
The present invention relates to an electrode device for electron emission and its fabrication method.
2. Description of the Related Art
(1) Electron Emission
According to conventional electrode techniques, emitters for electron emission have been formed by dispersing carbon nanotubes into slurry as conductive auxiliary and coating them on a metal cathode by screen printing (JP-A-11-111158, JP-A-11-111161, JP-A-2000-36243, JP-A-10-12124, GB 2353138). This method is simple, economical and easy to realize a large screen. There is another method by which carbon is grown in an alumina mold and a grown carbon column is used as an emitter (JP-A-2000-67736). With screen printing, however, it is difficult to control the number, vertical orientation and length of carbon nanotubes in an electrode in-plane and an ohmic contact with a cathode substrate, so that uniformity in the electrode in-plane cannot be realized. A mold carbon column is associated with a difficulty of controlling an ohmic contact and diameter so that an electric field is difficult to be raised and a large electric field is necessary for electron emission.
(2) Electrode
A spin transfer effect has been reported, which transfers magnetic spins by wiring a carbon naonotube between the source and drain. Fabrication of ultra fine transistors has also been reported. This fabrication utilizes the fact that metallic or semiconductive nature is presented depending upon a difference of chirality of single-walled carbon nanotubes. Metal electrodes are attached to both ends of single-walled carbon nanotubes forming several tens of bundles. Large current is flowed to realize resistance heating to selectively break only metallic nature carbon nanotubes and leave only semiconductive nature carbon nanotubes.
Since the size of a carbon nanotube is very small, it is difficult to process it and a large scale circuit is impossible to be fabricated by using such carbon nanotubes.
It is an object of the present invention to provide an electrode device for an electric field emission electron source suitable for duty drive having an element size of 50 xcexcm or smaller and an electrode device fabricating method.
The invention provides an electrode device which is fabricated by forming a glass film to be used as catalyst for forming carbon nanotubes, on a substrate to form metal catalyst at a nano meter level and control dispersion, dispersively forming carbon nanotubes on the metal catalyst and forming a metal coat on the surfaces of the carbon nanotubes to improve electric pulse response characteristics, and also provides a fabrication method for such an electrode device.
According to the method of fabricating a nano electrode device of the invention, uniform current is input and output in the in-plane of the device. More specifically, electron emission is realized which has no current loss to be caused by dielectric polarization. The current loss corresponds to the response characteristics of an output current relative to an input current. The amplitude and time of an output current responds sufficiently to the amplitude and time of an input current.
According to the fabrication method of the invention, a sputter glass film forming process quite different from conventional methods is introduced to efficiently form an electrode for electron emission.
According to the fabrication method of the invention, an acceleration voltage up to 50 keV can be applied.
The invention provides a display panel, a projector light source or an electron beam drawing apparatus mounted with an electron device capable of emitting electron beams at 50 keV or lower characterized in uniform electron beam emission in the in-plane of the electrode device. The electrode device has among others an emitter for electron beam emission, a grid for attracting electrons and a converging lens for converging electron beams, and can obtain a high current density.